Dilated cardiomyopathy is a common disease associated with high mortality rate, frequently related to lethal tachyarrhythmias. Currently there is no adequate way to predict who has high risk for arrhythmia and there is no way to warn of oncoming arrhythmias. Previous research in the John Hopkins Hospital demonstrated that QT variability is significantly altered in heart failure patients and in survivors of sudden cardiac death. The specific aims of Phase I are to further develop the hardware and software of our current patented QT monitor to enable real-time monitoring in clinical setup; to evaluate spacial and temporal distribution of QT variability along all 12 surface ECG leads to define the commercial configuration of the device; and to study additional clinical applications: early prediction of oncoming arrhythmias (by monitoring patients in the intensive cardiac care unit and hospitalized patients with frequent arrhythmias); detection of acute myocardial ischemia (by monitoring routine exercise stress test); risk stratification of sudden cardiac death failure patients (long term follow-up after baseline QT analysis). The QT variability algorithm provides validated and robust methodology for automatic, real-time monitoring of myocardial repolarization through standard ECG signals. PROPOSED COMMERCIAL APPLICATIONS: A device which can define high risk of arrhythmia is critical to better allocate resources for arrhythmia prevention. Its potential market is related to the 5 billion dollars global marker of ECG management devices: patient monitors, ECG recorders, holter systems, pacemakers, implanted defibrillators. We have already approached major biomedical medical device companies which show great interest in the QT monitor.